Hi   !
Would you take a look at:
https://support.google.com/plus/answer/1044955?it=en

Hello 00mlm27, Happy112.

If Happy112 answer can't fix the issue, then try the specific Mycroft Project - plugin.

thank you

To explain myself better: my problem is that whenever I type "xyz" in the url bar this is searched through google.it, while I want the result of the research to be under google.es. Thanks both of you for your answers though, I appreciated.

That's a different cup of tea ........ thank you for clarifying it  !
This will be a better 'place' for you to get help :
https://support.google.com/websearch/answer/873?es=en

In adddition: Would it help if you went to your Google profile and changed the language there  ? (works for me  !)

Just had a (tiny) brainwave: Try and install the latest Firefox version in the language of your choice here:
https://www.mozilla.org/en-US/firefox/all/
That should change google.it to google.es (I hope ...... )